Content is a collection of items in a portalArcGIS portal, also known as a portal, is a website with applications and tools that can be used to create, manage, access, and share geospatial content and data. It supports security and authentication, developer credentials, content and data service management, user and group management, and site administration. A portal can be hosted in Esri's infrastructure or your own infrastructure.Learn more that belong to a user, group, or organization. Content is also resources and data that are created, added, and managed in the portal. It includes a wide range of itemsAn item, also known as a content item, is a resource stored in a portal such as a web map, hosted layer, style, script tool, file, or notebook.Learn more such as mapsA map is a collection of layers that are displayed in 2D. It is typically composed of a basemap layer and data layers.Learn more, web appsA web app is a mapping, analysis, or data-driven application that runs in a web browser. In most cases they are configurable and are hosted in ArcGIS.Learn more, layersA layer is a reference to a collection of geographic data that is used to access and display data. The data for layers are typically provided by the basemap layer service and data services.Learn more, and other geospatial resources.